Artorius the Amiable
I'd never seen this npc before but bumped into him while wandering in Winterspring. Apparently he's part of a hunter quest. Which I somehow missed. He transforms into Artorius the Doombringer, a level 60 elite doomguard. Glad I didn't bump into him in that form. Also glad he didn't transform when I spoke to him - but I think you have to be on the quest for that to happen.